Comparative phylogeography of two Agarophyton species in the New Zealand archipelago. Issue 6 (18th August 2020)

• Record Type: Journal Article
• Authors: Huanel, Oscar R.; Nelson, Wendy A.; Robitzch, Vanessa; Mauger, Stéphane; Faugeron, Sylvain; Preuss, Maren; Zuccarello, Giuseppe C.; Guillemin, Marie‐Laure
• Editors: Krueger‐Hadfield, S.
• Is Part Of: Journal of phycology. Volume 56:Issue 6(2020:Dec.)
• Page Start: 1575
• Page End: 1590
• Publication Date: 2020-08-18
• Subjects: biogeographic and oceanographic barriers -- demography -- glacial–interglacial cycles -- Gracilariales -- ITS2 -- parapatric genetic clusters -- species co‐occurrence -- species diagnostic molecular tool; Algae -- Periodicals; 579.8
• DOI: 10.1111/jpy.13046
• Languages: English
• ISSNs: 0022-3646

Abstract

Abstract : Molecular studies have reported the coexistence of two species of Agarophyton in New Zealand: the newly described A . transtasmanicum with an apparently restricted distribution to some sites in the North Island, and the more widespread A . chilense . Here, we compared the distribution, genetic diversity, and structure of both Agarophyton species throughout the archipelago using sequences of the nuclear Internal Transcribed Spacer 2 (ITS2) marker. Agarophyton chilense' s distribution was continuous and extensive along the North and South Islands, Stewart Island, and Chatham Island, and the genetic clusters were mostly concordant with boundaries between biogeographic regions. In contrast, specimens of A . transtasmanicum were collected in four sites broadly distributed in both the North and South Islands, with no clear spatial structure of the genetic diversity. Populations, where the species co‐occurred, tended to display similar levels in genetic diversity for the two species. Demographic inferences supported a postglacial demographic expansion for two A . chilense genetic clusters, one present in the South Island and the eastern coast of the North Island, and the other present in northern South Island. A third genetic cluster located on the western coast of the North Island had a signature of long‐term demographic stability. For A . transtasmanicum, the skyline plot also suggested a postglacial demographic expansion. Last, we developed a new molecular tool to quickly and easily distinguish between the two Agarophyton species, which could be used to ease future fine‐scale population studies, especially in areas where the two species coexist.